Question 156
A 29-year-old male presents to an acute care clinic with complaints of a productive cough and fever to 38.7 degrees Celsius for the past 3 days, associated with some chest pain when he breaths and with chills. Physical examination reveals dullness to percussion on the left side of the chest. Crackles and a pleural rub are also heard at this location. A chest x-ray reveals consolidation of the left lung. A sputum culture is obtained and grows a pure sample of gram positive cocci in chains. Of the following, laboratory testing of this organism would reveal which of the following traits?
A. Not inhibited by optochin
B. Beta hemolytic
C. Bile soluble
D. Non-fermenter of glucose
E. Catalase positive
Answer for Question 156
Answer: C (Bile soluble)
Explanation: The presenting features are consistent with a community acquired pneumonia, consistent with a lobar pneumonia. A common cause of a lobar pneumonia is Streptococcus pneumoniae, which is gram positive and grows in chains. Streptococcus pneumoniae is bile soluble. It is also inhibited by optochin, alpha hemolytic, a fermenter of glucose, and catalase negative.
Question 157
Following a four day illness that was characterized by a high fever (up to 41 degrees Celsius) and severe muscle aches, a 29-year-old male presents to the emergency room with complaints of dyspnea with exertion, chest pain which is worse with expiration, and a productive cough. Physical examination reveals dullness to percussion on the left side of the chest. Crackles and a pleural rub are also heard at this location. A chest x-ray reveals consolidation of the left lung. A sputum culture is obtained and grows a pure sample of gram positive cocci in clusters. Of the following, laboratory testing of this organism would reveal which of the following traits?
A. Catalase negative
B. Coagulase positive
C. Alpha hemolysis
D. Non-fermenter of glucose
Answer for Question 157
Answer: B (Coagulase positive)
Explanation: The preceding illness has features of influenza (high fever and myalgias). One complication of influenza is the subsequent development of a secondary bacterial infection. In this situation, the patient developed Staphylococcus aureus, which is a common etiologic agent of a secondary bacterial infection in patients with influenza. Staphylococcus aureus is coagulase positive. It is also catalase positive, beta hemolytic and a fermenter of glucose.
Question 158
A 73-year-old male with the history of a stroke 2 years ago that left him with residual motor difficulties in eating is brought to the emergency room by his family because over the past three weeks he had developed a productive cough with foul-smelling sputum. In addition, he has lost about 10 lb. and has an intermittent fever (although his temperature wasn’t taken). He has no history of tobacco use. A chest x-ray reveals an infiltrate in the lower lobe of the right lung. Of the following, what is the most likely diagnosis?
A. Community acquired bacterial pneumonia
B. Community acquired viral pneumonia
C. Aspiration pneumonia
D. Mycobacterium tuberculosis
E. Necrotic pulmonary neoplasm
Answer for Question 158
Answer: C (Aspiration pneumonia)
Explanation: Elderly individuals, especially those with a history of a condition that would cause neuromuscular impairment, such as a stroke, are at risk for aspiration pneumonia. Because aspiration pneumonia often involves anaerobic bacteria and/or abscess formation, the patient can produce foul-smelling sputum. With aspiration pneumonia, patients often present over weeks or months and can have fever and weight loss. The lower lobes are affected, and more often the right side than the left side as the angle of the right bronchus allows for aspirated material to more easily enter the right lung.